[PatrickHenry]

It seems we only find fossils for species that once were successful. Where are the fossils of the unsuccessful ones?

BB, my delight! I'm so glad you asked.

Of all species living today (ignoring stuff like bacteria, flatworms, sponges, horseshoe crabs and insects), sharks have probably been around the longest. There is evidence that modern sharks first appeared about 100 million years ago. Because virtually all other present-day species emerged later, it is highly likely -- perhaps even obvious -- that all fossils of now-extinct species are either: (a) non-transitional dead-ends; (b) transitional, but leading to eventual dead-ends; or (c) transitional and leading to species now living.

Links to useful information:
Taxonomy, Transitional Forms, and the Fossil Record.
The Fossil Record: Evolution or "Scientific Creation" by Cuffey.

[MHGinTN]

In my reading the other day it was interesting to notice that even the 'Cambrian Explosion' fossil record contains what are very likely transitional species (worms with stubby legs, for instance). Now that I'm noticing the transitionals in my reading, they seem to be 'accumulating at an astonishing pace'!